How Do I Tell What Size Of Breaker Box I Have?

Many people don’t give a thought to their electrical box until something quits working. You might have to brush away cobwebs to get the door opened up depending on how long it’s been since the last breaker was tripped. Maybe today you are thinking about adding an electric garage heater, hot tub, tesla charger, air compressor, welder, or some other large 240 volt load and wondering if you have enough capacity to handle the extra load. Let us guide you through the process of finding out what size of breaker panel you have so you have a better handle on your home’s electrical system.

To start with, we want to make sure that we are looking in the proper breaker box. The easiest way to tell if you are on the main box in your house is to check where the electric meter is and make sure that you are in close proximity to that. That is the best way to tell if you are at the first and main breaker box in the house. Sometimes there are additional electrical panels fed out of that main box which is called a sub panel.  They can often be located in other areas of the house or garage, but we want to find the overall capacity of the house, which would be limited by the first breaker coming from the meter. It is very common to find the main electrical boxes located in a basement utility room. Once you locate your main breaker box, if you open up the door, there is usually a larger sized breaker on the top part of the box although it can also be located in the bottom. Oftentimes it will say “main” and it will be completely separated from the two rows of breakers. If you look on the handle, there should be an engraving of how many amps of capacity the main breaker has. The most common sizes are 100, and 200 amps, although there are a handful of 150 amp breaker boxes as well.

Once you determine what size of total capacity you have, you may be wondering what you can do with that amount of power. If you have a 100 amp box a good rule of thumb is that there is likely enough capacity there to take care of an electric stove, water heater, dryer, and air conditioner. Once you start adding things above and beyond such as hot tubs, electric car, chargers, large electric saunas or garage heaters, etc. you can start running into capacity issues. With a 200 amp box there is a lot more capacity which allows you to run many other items that are large power draws without overloading the system. However, even with 200 A there are some situations where you could run into capacity issues if you have a lot of 240 volt electric equipment.